Distributions of highly branched isoprenoid alkenes and other algal lipids in surface waters from East Antarctica: further insights for biomarker-based paleo sea-ice reconstruction
The occurrence and variable abundance of certain di- and tri-unsaturated C 25 highly branched isoprenoid (HBI) biomarkers in Antarctic marine sediments has previously been proposed as a possible proxy measure of paleo sea-ice extent in the Southern Ocean. In the current study, we obtained 47 near-su...
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Pergamon-Elsevier Science Ltd
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Online Access: | https://doi.org/10.1016/j.orggeochem.2016.02.011 http://ecite.utas.edu.au/107410 |
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ftunivtasecite:oai:ecite.utas.edu.au:107410 2023-05-15T14:03:26+02:00 Distributions of highly branched isoprenoid alkenes and other algal lipids in surface waters from East Antarctica: further insights for biomarker-based paleo sea-ice reconstruction Smik, L Belt, ST Lieser, JL Armand, LK Leventer, A 2016 https://doi.org/10.1016/j.orggeochem.2016.02.011 http://ecite.utas.edu.au/107410 en eng Pergamon-Elsevier Science Ltd http://dx.doi.org/10.1016/j.orggeochem.2016.02.011 Smik, L and Belt, ST and Lieser, JL and Armand, LK and Leventer, A, Distributions of highly branched isoprenoid alkenes and other algal lipids in surface waters from East Antarctica: further insights for biomarker-based paleo sea-ice reconstruction, Organic Geochemistry, 95 pp. 71-80. ISSN 0146-6380 (2016) [Refereed Article] http://ecite.utas.edu.au/107410 Earth Sciences Physical Geography and Environmental Geoscience Physical Geography and Environmental Geoscience not elsewhere classified Refereed Article PeerReviewed 2016 ftunivtasecite https://doi.org/10.1016/j.orggeochem.2016.02.011 2019-12-13T22:08:25Z The occurrence and variable abundance of certain di- and tri-unsaturated C 25 highly branched isoprenoid (HBI) biomarkers in Antarctic marine sediments has previously been proposed as a possible proxy measure of paleo sea-ice extent in the Southern Ocean. In the current study, we obtained 47 near-surface (ca. 010m) water samples taken from locations in East Antarctica with different sea ice settings and analysed them for their HBI, sterol and fatty acid content. Sampling locations ranged from the permanently open-ocean zone (POOZ), with no seasonal sea-ice cover, the near-shore summer sea ice zone (SIZ), where sea ice remains long into the summer melt season, and the marginal ice zone (MIZ), located between the POOZ and the SIZ, and with a highly variable latitudinal sea-ice edge throughout the season. A di-unsaturated C 25 HBI (diene II) was only identified in surface waters from the MIZ and the SIZ, consistent with a sea-ice diatom origin for this biomarker. In contrast, a tri-unsaturated C 25 HBI (triene III) was detected in all samples from the POOZ, the MIZ and the SIZ, and with a stable isotopic composition (δ 13 C=−351.5) consistent with a phytoplankton source. The highest concentrations of diene II and triene III were in samples from the SIZ and the MIZ, respectively, thus providing further insights into the sea-ice conditions likely favourable for their production and how their relative abundances (the II/III ratio) in underlying sediments might be better interpreted for paleo sea-ice reconstruction. In this respect, relatively high II/III might be a good indicator of extended (into summer) seasonal sea-ice cover, while lower II/III may provide a better indicator of the MIZ. However, the observation of highly variable II/III within the polynya setting of the SIZ may also have significant impacts on sedimentary values. Distributions of diatom sterols and fatty acids were also variable between the three sampling zones, but these were not as distinctive as those observed for the HBIs. Article in Journal/Newspaper Antarc* Antarctic Antarctica East Antarctica Sea ice Southern Ocean eCite UTAS (University of Tasmania) Antarctic East Antarctica Southern Ocean Organic Geochemistry 95 71 80 |
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Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Earth Sciences Physical Geography and Environmental Geoscience Physical Geography and Environmental Geoscience not elsewhere classified |
spellingShingle |
Earth Sciences Physical Geography and Environmental Geoscience Physical Geography and Environmental Geoscience not elsewhere classified Smik, L Belt, ST Lieser, JL Armand, LK Leventer, A Distributions of highly branched isoprenoid alkenes and other algal lipids in surface waters from East Antarctica: further insights for biomarker-based paleo sea-ice reconstruction |
topic_facet |
Earth Sciences Physical Geography and Environmental Geoscience Physical Geography and Environmental Geoscience not elsewhere classified |
description |
The occurrence and variable abundance of certain di- and tri-unsaturated C 25 highly branched isoprenoid (HBI) biomarkers in Antarctic marine sediments has previously been proposed as a possible proxy measure of paleo sea-ice extent in the Southern Ocean. In the current study, we obtained 47 near-surface (ca. 010m) water samples taken from locations in East Antarctica with different sea ice settings and analysed them for their HBI, sterol and fatty acid content. Sampling locations ranged from the permanently open-ocean zone (POOZ), with no seasonal sea-ice cover, the near-shore summer sea ice zone (SIZ), where sea ice remains long into the summer melt season, and the marginal ice zone (MIZ), located between the POOZ and the SIZ, and with a highly variable latitudinal sea-ice edge throughout the season. A di-unsaturated C 25 HBI (diene II) was only identified in surface waters from the MIZ and the SIZ, consistent with a sea-ice diatom origin for this biomarker. In contrast, a tri-unsaturated C 25 HBI (triene III) was detected in all samples from the POOZ, the MIZ and the SIZ, and with a stable isotopic composition (δ 13 C=−351.5) consistent with a phytoplankton source. The highest concentrations of diene II and triene III were in samples from the SIZ and the MIZ, respectively, thus providing further insights into the sea-ice conditions likely favourable for their production and how their relative abundances (the II/III ratio) in underlying sediments might be better interpreted for paleo sea-ice reconstruction. In this respect, relatively high II/III might be a good indicator of extended (into summer) seasonal sea-ice cover, while lower II/III may provide a better indicator of the MIZ. However, the observation of highly variable II/III within the polynya setting of the SIZ may also have significant impacts on sedimentary values. Distributions of diatom sterols and fatty acids were also variable between the three sampling zones, but these were not as distinctive as those observed for the HBIs. |
format |
Article in Journal/Newspaper |
author |
Smik, L Belt, ST Lieser, JL Armand, LK Leventer, A |
author_facet |
Smik, L Belt, ST Lieser, JL Armand, LK Leventer, A |
author_sort |
Smik, L |
title |
Distributions of highly branched isoprenoid alkenes and other algal lipids in surface waters from East Antarctica: further insights for biomarker-based paleo sea-ice reconstruction |
title_short |
Distributions of highly branched isoprenoid alkenes and other algal lipids in surface waters from East Antarctica: further insights for biomarker-based paleo sea-ice reconstruction |
title_full |
Distributions of highly branched isoprenoid alkenes and other algal lipids in surface waters from East Antarctica: further insights for biomarker-based paleo sea-ice reconstruction |
title_fullStr |
Distributions of highly branched isoprenoid alkenes and other algal lipids in surface waters from East Antarctica: further insights for biomarker-based paleo sea-ice reconstruction |
title_full_unstemmed |
Distributions of highly branched isoprenoid alkenes and other algal lipids in surface waters from East Antarctica: further insights for biomarker-based paleo sea-ice reconstruction |
title_sort |
distributions of highly branched isoprenoid alkenes and other algal lipids in surface waters from east antarctica: further insights for biomarker-based paleo sea-ice reconstruction |
publisher |
Pergamon-Elsevier Science Ltd |
publishDate |
2016 |
url |
https://doi.org/10.1016/j.orggeochem.2016.02.011 http://ecite.utas.edu.au/107410 |
geographic |
Antarctic East Antarctica Southern Ocean |
geographic_facet |
Antarctic East Antarctica Southern Ocean |
genre |
Antarc* Antarctic Antarctica East Antarctica Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Sea ice Southern Ocean |
op_relation |
http://dx.doi.org/10.1016/j.orggeochem.2016.02.011 Smik, L and Belt, ST and Lieser, JL and Armand, LK and Leventer, A, Distributions of highly branched isoprenoid alkenes and other algal lipids in surface waters from East Antarctica: further insights for biomarker-based paleo sea-ice reconstruction, Organic Geochemistry, 95 pp. 71-80. ISSN 0146-6380 (2016) [Refereed Article] http://ecite.utas.edu.au/107410 |
op_doi |
https://doi.org/10.1016/j.orggeochem.2016.02.011 |
container_title |
Organic Geochemistry |
container_volume |
95 |
container_start_page |
71 |
op_container_end_page |
80 |
_version_ |
1766274084696489984 |